Rocky Intertidal Benthos in Iniskin/Iliamna Bay

1
Rocky Intertidal Benthos in Iniskin/Iliamna Bay
a 28-Year Baseline and Hints of Climate Change?

• Investigators
• Jon Houghton, Ph.D., J. Stutes, Ph.C., D.
  Ormerod, P.E. (Pentec Environmental/Hart
  Crowser)
• Dennis Lees, M.S. and
• Sandra Lindstrom, Ph.D.
• (Independent)
• January 24, 2007

2
Pebble Infrastructure Port Road
3
Area Sampling History

• 1976-78 OCSEAP
• IT Rock (3 sites)
• IT Soft (1 site)
• 1996 CIRCAC
• IT Rock (2 sites)
• IT Soft (1 site)

4
Study Goals

• Gain understanding of benthic assemblages in
  areas that may be affected by road/port
  development
• Existing conditions for use in project design and
  permitting
• Baseline for long- term monitoring

5
Study Objectives

• Build on background (1970s, 1996)
• Collect info on new sites
• ID important habitats (kelp, eelgrass, rookeries)
• (Explore relict arctic biota question)

6
Intertidal Sites (2004-2006)
7
2004-2006 Rocky IT Sample Design

• Similar to 1978 and 1996
• Stratified Random Design
• Intertidal quadrat sampling
• Fixed transects, elevations, random quad
  positioning
• Photographs
• Quantitative density/cover by species

8
Knoll Head Upper Q 1

• lt 1996
• 2004 gt
• lt2005
• 2006gt

9
Rocky Shoreline Characteristics

• Varied substrates/ slopes
• Bed rock benches
• Cliffs/steep slopes
• Boulder/cobble
• Stressors
• Rock weathering

10
Stressors

• More Stressors
• Exposure to Kamishak Bay
• Wind generated waves, turbidity
• Ice
• Assemblages not rich or diverse (except low)

11
Winter Stressors Intra-annual Var.

12
Scott Island Low Intertidal Transect
June 1996
April 2006
       

August 2004
13
Intra-annual Variability

• Scott Island
• Macroalgae 1978 (Lees et al. 1980)

14
       

15
       

16
Rocky Shorelines

• Upper intertidal
• Barnacles, limpets, littorines, Porphyra
• Few mussels, patchy Fucus
• More spp. in sheltered cracks reds, hermits,
  Nucella

17
Inter-annual VariabilityUpper/Mid Elevation
Inverts.
18
Rocky Shorelines (cont.)

• Middle intertidal
• Algae dominated Fucus, Palmaria spp.
• Few animals barnacles, Lacuna, limpets,
  Halichondria

19
Knoll Mid Rock

• lt 1976-78 OCSEAP
• lt 2004 Pebble

• 1996 CIRCAC gt
• 2005 Pebble gt

20
Knoll Head(mid)
21
Mid Elevation Algal Cover
22
Rocky Shorelines (Lower)

• Lower intertidal (boulder/bedrock flats)
• More diverse Saccharina, Alaria, several reds,
  corallines
• More diverse fauna hermits, shrimp, chitons,
  sea stars, limpets, blennies, sponges
• In sediment pockets
• Littlenecks, Macoma spp., Mya, Glycera, Echiurus
• Herring spawn?

23
Habitats of Special Interest

• Kelp
• Common on all low IT/shallow ST rock (Saccharina,
  Alaria)
• Moderate beds off Knoll Head, North Head
• Herring spawning?

24
Summary

• Diverse habitats
• High stress environment
• Low to moderate primary productivity and
  diversity
• Probable importance to adjacent Kamishak Bay
  ecosystem
• Organic input
• Nursery for salmon, FF, and crab
• Long-term trends
• Algal dominance
• Species shifts
• Still evaluating importance as relict arctic biota

25
2004-2006 Field Work

• Habitat Mapping
• Rocky intertidal sampling
• Herring spawn surveys
• Tissue samples

26
Soft Intertidal (2004 2005)

• Soft intertidal sampling
• Transects, elevations, 0.009-m2 cores
• Photographs
• Quantitative density/cover by species
• Macro-cores (2005)
• Sed./Tissue samples

27
Soft Shorelines

• Wide range of soft substrates
• Mud/silt
• Gravel
• Mixed
• Sand
• Stressors
• Ice
• Glacial silt
• Wave action

28
Soft Shorelines (cont.)

• Sand/gravel
• Few plants or animals
• Mixed (incl. pockets in boulder beaches)
• Macoma spp., Mya, Glycera, Echiurus
• Mud/silt
• Bivalves (esp. Mya, Macoma) polychaetes, hermits

29
Intertidal Infauna (2004-2005)

• Highly variable substrates, but
• Relatively uniform w/in stations
• High stress (ice,waves, silt)
• Less rich/diverse than ST
• Low gradient means few large predators
  (snails/stars)
• Dominants (biomass)
• Macoma spp.
• Nephtys spp.
• Mysella sp
• Echiurus sp.
• Cistenides sp.
• Leitoscoloplos sp.

Photo credits MBARI and MBL
30
Intertidal Infauna (2004-2005) Macroinfauna By
Abundance
2005
2004
31
Intertidal Infauna (2004-2005) Macroinfauna By
Biomass
2005
2004
32
Intertidal Infauna (2004-2005) Megainfauna
By Biomass
By Abundance
33
Study Objectives (Subtidal)(Lee Ann Gardner, RWJ
Consulting Steve Jewett, UAF)

• Subtidal recon at port sites
• Benthic infauna
• Diver transects
• ID important habitats (kelp, eelgrass)
• Gain insight for planning future work

34
Subtidal Sampling (2004)
35
Subtidal Infauna (2004)
Terebellidae

• Relatively uniform substrate
• Higher var. w/in stations
• Lower stress
• More rich/diverse than IT
• More larger predators (snails/stars)
• Dominants (biomass)
• Macoma spp.
• Nephtys spp.
• Terebellidae
• Lumbrineris spp
• Praxillella sp.
• Yoldia sp.

Nephtys sp
Photo credits MBARI, UCSC, and MBL
36
Subtidal Infauna (2004)
By Abundance
By Biomass
37
Diver Transects (2004)

• Bedrock reefs
• Boulder flats
• Mixed pebble/cobble with silt
• Fairly uniform sand/silt

38
Habitats of Special Interest

• Eelgrass
• Small patches in Iniskin
• Small patches in Illiamna
• Largest patches seen in Cottonwood entrance

39
Bird/Mammal Observations

• Bald eagles
• Peregrine falcon
• P. guillemots, puffins, murrelets, scoters,
  harlequins
• Seals
• Whales

40
Intertidal Habitat Mapping
41
Intertidal Habitat Mapping